(1) Field of the Invention
The present invention relates to a lubricating oil composition, and more specifically, it relates to a lubricating oil composition which comprises as the main components, a base oil, a specific hindered phenol compound, a specific alkylated diphenylamine compound and a borated succinic acid imide compound, is excellent in heat resistance and oxidation stability, and stably functions for a long period of time particularly as a traction drive oil, a compressor oil or the like which is exposed to a high temperature in a mist-like state.
(2) Description of Related Art
In recent years, continuously variable transmissions (CVT) of traction drives for cars have shifted toward the increase in transmission power, the miniaturization of size and the freedom from maintenance. With this shift, a lubricating oil is required to have heat resistance and oxidation stability at a high temperature, and the level of these requirements is rising year by year.
Heretofore, research and development have been made mainly to secure the heat resistance and the oxidation stability at a high temperature in the so-called oily phase portion, and therefore the already developed lubricating oils can scarcely inhibit heat deterioration and oxidation deterioration in a gaseous phase portion.